@Dušica0
you can click on "report" link. You will find it under the guest's photo , on the left side of your message thread.
You can click on a flag icon at your message thread if some of his messages were offensive , threatening or else...
If your guest already checked out then you can leave him a bad review and explain what was wrong with your guest in a private message to Airbnb (the last text area after you leave a public review)
If your guest is still at your place then contact Airbnb and ask them to relocate your guest : https://www.airbnb.com/help/contact_us#/ you can request a call from Airbnb and they will call you very soon (so I've heard).